Experimental Study Of Washability And Law Of Liberation In Middlings Coal By Crushing

Coal resources is rich in China,but coking coal reserves is poor and other coal couldn’t replace coking coal in the metallurgical industry at present.Most of the coking coal in coal preparation plant contain a certain amount of coking components, but it is used as fuel directly causing serious waste of resources because of the high ash content and sulfur content, low calorific value.lt is the effective ways to reduce environmental pollution,improve the utilization rate of coal,save resources,improve the profit that crushing minerals and clean coal separation,recycling clean products.The article study the law of crushed liberation and recleaning experimental research with middlings coal in coal preparation plant.Itprovide the technical support for the development of middlings coal recleaning.It treat dense medium middlings coal of Tunlan coal preparation plant as experimental coal sample.Analyzing the density of coal sample and crushing to-3mm.When the requirement for ash content of10%,the cleaned coal yield of Tunlan coal preparation plant increased from6.5%to20%.It illustrated Coal crushing solution is feasible.Mesh were used respectively to25mm,13mm,6mm and3mm standard screen to sieve of coal sample.The greater of Middlings coal grade,the lower the yield of the<1.45kg/L density grade product,the lower the ash content.Each size fraction of different density level coal crushed-3mm,study ash content, production rate,sulfur content,caking property,volatile,reflectivity of<1.45kg/L density level product.Results show that the same density level and differentsize fraction of coal samplescrushed to3mm,the greater of size fraction,the lower the ash content of<1.45kg/L density grade product,the higher the production rate.The same size fraction and different density level of middlings coal crushed to-3mm,the lower the density level, the higher the yield of <1.45kg/L density level product, the lower the ash content, the higher the bonding;sulfur content, volatile and reflectivity is unchanged as the change of size fraction and density level.It use3mm standard sieve sieve of middlings coal samples in Shaqu coal preparation.It is concluded that low density grade product mainly exist in the natural grade level-3mm through the analysis of levels of natural-3mm and broken-3mm density composition.Study law of liberation in middlings coal by crushing in each grade.Results show that the greater of middlings coal grade, the lower the yield of the <1.40kg/L density grade product.The same size fraction and different density level of middlings coal crushed to-3mm,the higher the density level, the lower the yield of <1.40kg/L density level product, the lower the ash content,butthe higher of ash content of coal slime.1.40-1.60kg/L and1.60-1.80kg/L of each grade crushed to-3mm and coal slime put floation test. When the dosage of kerosene is30g/t, the dosage of2-octanol is20g/t, it could not get the qualified concentrate.Constructed to gravity concentration "remove head",grinding-flotation as characteristic for the depth of the coking coal separation technology.Results show that:(1)the natural grade-3mm middlings coal using coal slurry cyclone gravity separation column to improve the separation, it can be produced at a rate of9.73%, the ash is10.23%;in underflow coal grinding-flotation experiment, the grinding time for2min, the dosage of kerosene is30g/t, the dosage of2-octanol is20g/t, and it can get flotation plant production rate is38.04%, ash content is9.41%.(2)broken level-3mm middlings coal using coal slurry cyclone gravity separation column to improve the separation,it can be produced at a rate of0.69%, the ash content is9.68%; in bottom flow coal grinding-flotation experiment, grinding time of2 min, the dosage of kerosene is30g/t, the dosage of2-Octanol is20g/t, and it can get flotation plant production rate is0.62%, ash content is9.04%.It shows that it can be recycled from middlings coal that production rate is10.85%, ash content is9.60%after gravity concentration, underflow grinding-flotation separation process.